High-reliability all-fiber FIR temperature sensor using LiGd(WO4)2:Er3+/Yb3+ phosphors

Abstract

Rare earth doped LiGd(WO4)2 phosphors have been prepared by solid sintering technology. The dominant 4G5/2→6H9/2 emission of Sm3+ ions suggests that Sm3+ ions occupy the non-centrosymmetric lattices in LGWO:Sm3+ phosphors. Under the excitation at 980 nm laser, bright green upconversion emissions at 531 nm and 553 nm were detected in LGWO:Er3+/Yb3+ phosphor, which was used to build a high-reliability temperature sensor based on fluorescence intensity ratio (FIR) technology. The calibration curve between FIR and temperature was established at the temperature range of 258–423 K. The highest absolute sensitivity was 0.0137 K−1 at 423 K and the standard deviation of multiple temperature measurements at 313 K was only 0.108%. Experimental data show that this material can be used for the all-fiber temperature sensors.